Information wanted - Olympus RD35

[wilwahabri]

I have a very nice Olympus RD35 with a six element 40mm f1.7 lens. It is rumored that the lens configuration was the basis for the 40mm F.Zuiko f2 lens, which is unusually of the Sonnar design. Does anyone know what the lens configuration for the 40mm f1.7 lens fitted to the RD35 is? or where I could find out?

Opinion varies, a lens of that physical size and specification may be a Tessar, but I believe 6 elements would not be a Tessar form?

Help appreciated

Many thanks

Bill

 

[xkaes]

This won't be of much help, but there were several other 40mm f1.7 lenses on other cameras during the same period, and they probably all used the same optical design -- whatever that is. Here's several of them -- let us know what you find:

http://www.subclub.org/minman/leanmean.pdf

Olympus 35 RD - Olympus' Final 40mm Rangefinder

It was 1975 when Olympus made the call to launch their final Hail Mary in the competitive 40mm fixed-lens rangefinder game. Olympus engineers aimed to better the already well-received Olympus 35 SP and replace it with the RD (short for Rangefinder Deluxe) in hopes of making their last...

casualphotophile.com

 

[reddesert]

The 35RD manual just says it is 6 elements in 4 groups but unfortunately does not show a cutaway diagram. A six-element f/1.7 lens is certainly not a Tessar. Tessars have four elements and are usually at fastest f/2.8 in a taking lens. Typically, a six-element fast lens that is normal focal length is a double Gauss design.

In many double Gauss designs for normal focal lengths, there are mild asymmetries between the front and back groups, while a Sonnar is more asymmetric front-back. You might be able to tell the difference by looking at the reflections of a light source off the surfaces in the lens, but it will be easier if you have examples of a double Gauss (such as most normal 50mm SLR lenses) and a Sonnar to compare to. Some diagrams here:
https://en.wikipedia.org/wiki/Double-Gauss_lens
https://en.wikipedia.org/wiki/Zeiss_Sonnar

 

[OAPOli]

Maybe OP is on to something. Looking at the service manual for the 35 DC, which most likely has the same lens as the RD, you can sort of see the lens elements. The rear section may indicate a Sonnar design but it is hard to tell.

 

[OAPOli]

Nevermind. Next page has this:

 

[__Brian]

There are not too many Fixed-Lens Rangefinder cameras with Sonnar formula lenses. The Walz 35 with a 48mm F1.9 come to mind- 7 elements in 3 groups.

Rollei had the 35-XF with a 40mm F2.3 (I had to look).